This short video explores the invisible particles floating in the air around us, from dust and pollen to PM2.5 and volatile organic compounds. Understanding what's in your air is the first step to breathing cleaner.
This video explains how poor indoor air quality affects your respiratory system and lung health. Understanding the connection between the air you breathe and your lungs helps motivate better air quality practices at home.
No. AQI reflects outdoor air at monitoring stations, not the air inside your home. Indoor air quality depends on: outdoor pollution entering the home, ventilation, indoor sources (cooking, dust, incense, smoking), and use of air purifiers or filters. AQI is a risk indicator, not an indoor measurement.
The main indoor air pollutants are: PM2.5 and PM10, VOCs (from paints, cleaning products, new furniture, mothballs), CO₂ (indicates poor ventilation), NO₂ (from gas stoves), and biological pollutants (mould, pet dander, dust mites, pollen). In Indian homes, cooking emissions and outdoor pollution infiltration are often the biggest contributors.
Common VOC sources to minimise: synthetic air fresheners, oil-based paints and adhesives, new pressed-wood furniture, nail polish, mosquito coils, naphthalene mothballs, and scented candles. Bleach and ammonia are worth using carefully too, but they irritate as inorganic gases, not as VOCs. Treat 'low-VOC' and 'zero-VOC' labels as a starting point, not a guarantee.
Yes. Measurements in Ahmedabad, Gandhinagar and New Delhi all found the VOCs they measured were higher indoors than outdoors. The sources are inside the house: cooking, plastics, consumer products, furniture, cleaners. Outdoor AQI does not tell you this number.
Mostly because windows stay shut. A Gujarat study found indoor totals averaged 327 µg/m³ in winter against 150 µg/m³ in summer. Gorakhpur homes showed the same winter peak for BTEX. Closed rooms trap whatever is being used inside.
No health-based standard exists for total VOCs in homes, in India or elsewhere. The 500 µg/m³ figure you will see is a LEED building-rating threshold, not a health limit. Total VOC is also a lump sum. Formaldehyde, benzene and limonene are not interchangeable, so which compounds are present matters more than the single number.
No. Fragrance formulas are treated as proprietary. One word can stand in for dozens of compounds. Tests of best-selling fragranced products have found nearly 100 VOCs across six packs, with none of them printed on the label. Treat the ingredient list as a floor, not a full account.
Not automatically. Citrus and pine scents contain terpenes such as limonene and pinene. Those react with ozone already present indoors and form formaldehyde and ultrafine particles. “Plant-derived” describes origin, not indoor behaviour. An unscented version of the same cleaner avoids that chemistry.
Better not to, if the device produces ozone. Ozone is what turns terpenes into secondary pollutants, so the pair is worse than either alone. If a cleaner lists limonene or pinene and you are unsure whether your ioniser makes ozone, establish that first.
No. HEPA catches particles. VOC molecules are far smaller. Only sufficient activated carbon addresses gases. If terpene–ozone chemistry is producing ultrafine particles, HEPA helps with those particles — not with the original VOC.
Not necessarily. Water-based paints and surface cleaners often contain glycol ethers, which are VOCs. The phrase describes the carrier, not the full formula. Read the named ingredients, or run the pack through the [VOC Ingredient Checker](/tools/voc-checker/).
Mostly from particleboard and urea-formaldehyde furniture: plywood wardrobes, modular kitchens, laminate flooring. Some cleaners and cosmetics use formaldehyde-donor preservatives, but the move-in spike is almost always the boards. WHO's indoor guideline is 0.1 mg/m³ as a 30-minute average.
Yes. Naphthalene has its own WHO indoor guideline: 0.01 mg/m³ as an annual average. Without mothballs, indoor naphthalene usually sits near the detection limit; with them, levels can rise up to a hundredfold. WHO's own conclusion was that the surest protection is to stop using them altogether. They have been banned as pesticides in the EU since 2008 and remain widely sold in India. Cedar or lavender is enough if you only need a deterrent.
Use the [VOC Ingredient Checker](/tools/voc-checker/). Tap a preset for common Indian products, paste the ingredient list, or photograph the pack. Where WHO 2010 set an indoor guideline — formaldehyde, benzene, naphthalene — the tool screens against that. For terpenes and glycol ethers it uses the indoor-chemistry literature instead.
Yes, but only well-fitting respirators. N95, FFP2 and KN95 respirators filter at least 94–95% of fine particles when they seal properly against the face. Surgical masks, cloth masks and dupattas leak heavily around the edges and offer far less protection against PM2.5.
They are equivalent standards from different regions: N95 (US, 95% filtration), FFP2 (Europe, 94%) and KN95 (China, 95%). Any of the three works for pollution if it is genuine and fits well. Counterfeits are common in India, so buy from reputable sellers and check for standard markings on the mask itself.
Yes. Even a genuine N95 loses most of its benefit if air leaks around the nose, cheeks or chin. A snug fit with both straps worn correctly, the nose clip pressed firm, and no facial hair breaking the seal matters as much as the filter rating.
For personal pollution protection, valved respirators filter the air you breathe in just as well and feel cooler to wear. The drawback is that your exhaled air exits unfiltered, so they do not protect others if you are unwell. For smog protection alone, a valve is acceptable.
No. Washing destroys the electrostatic charge that makes the filter effective. Respirators are designed for limited reuse: replace them when they become dirty, damaged, damp or harder to breathe through. Storing a used mask in a clean, breathable bag between uses is fine.
No. Standard N95/FFP2/KN95 respirators filter particles only. Gases such as ozone, NO₂ and VOCs pass straight through. On high-AQI days, a respirator handles the particle side of smog; reducing time outdoors during peak hours remains the main defence against the gas side.
Yes, when correctly sized and used in a closed room. True HEPA filters reduce PM2.5, dust, pollen, and smoke. CADR and room size matter.
They reduce particles like PM2.5, dust, allergens, and smoke. They cannot fix CO₂ buildup, humidity, or poor ventilation. They also do not remove VOCs unless the unit has enough activated carbon.
No. Air purifiers do not add oxygen or remove CO₂. Ventilation is required for that.
HEPA filters can capture airborne particles that carry viruses and bacteria, but they don't kill them. Some purifiers add UV-C light or ionisers for germ-killing, but effectiveness varies. Air purifiers are not a substitute for ventilation, masks, or hygiene practices during illness.
Air purifiers do not dry the air and do not reduce humidity in a room. They work by filtering particles from the air, not by removing moisture. They do not heat, cool, or dehumidify the air. This confusion usually happens because in winter, the air is already quite dry. Running heaters further reduces indoor relative humidity, and any increased airflow intensifies the sensation of dryness on your skin and mucous membranes. The purifier itself does not change humidity levels.
No, they serve completely different purposes. Air purifiers clean the air by removing particles like dust, pollen, smoke, and PM2.5 using filters (typically HEPA). Humidifiers add moisture to the air to increase humidity levels. An air purifier won't make dry air more humid, and a humidifier won't clean polluted air. Some combo units exist, but they're generally less effective at both tasks than dedicated devices.
No. The human body does not build 'immunity' to air pollution. Air pollution is not like germs or infections, where controlled exposure can sometimes train the immune system. Pollution causes damage, not immunity.
No. What can happen is: when someone moves from clean air to polluted air, irritation is more noticeable. That's awareness, not reduced immunity. The pollution was always harmful. The body just wasn't constantly inflamed before.
Not meaningfully. The NASA study often cited was done in sealed chambers, not real rooms. In typical homes, you would need hundreds of plants to see any effect. Plants are great for mood and decor, but not for air cleaning.
No. These wearable devices are marketed as negative ion generators that clean the air around you, but studies show they can actually increase ozone concentration in your breathing zone. Ozone is a lung irritant and exposure levels from these devices can exceed health-based air quality standards. Stick with room-based HEPA air purifiers for effective particle removal.
Look for true HEPA (H13 or higher) for particles. Add activated carbon if the home has VOC sources: paint, adhesives, mothballs, fragranced cleaners, new furniture. Do not use smell as the test. Formaldehyde and several other VOCs are poorly detected by the nose at levels that still matter.
In practice, a well-designed HEPA 13 purifier with proper airflow performs almost as well in homes.
One purifier cleans one room. Multiple rooms usually require multiple units.
An air purifier removes particles and gases from the air using filters. HEPA captures PM2.5, pollen, and dust; activated carbon handles VOCs and odours. A dehumidifier removes excess moisture from the air, reducing humidity to prevent mould, dust mites, and that sticky monsoon feeling. They solve different problems. In an Indian home during monsoon, you may need both: a dehumidifier for humidity control and an air purifier for outdoor pollution entering through gaps. See our [Dehumidifier FAQs for Indian Homes](/posts/dehumidifier-faqs-indian-homes) for sizing guidance.
The CADR printed on air purifier packaging is measured at the highest fan speed, which is often too noisy for continuous use, especially at night or during work. At lower, quieter speeds, the actual CADR drops significantly. To maintain effective air cleaning at comfortable noise levels, choose an air purifier with a CADR 20-30% higher than your calculated room requirement. This allows you to run the purifier on low or medium mode while still achieving adequate air changes per hour.
A PM2.5 sensor is essential. A TVOC sensor is useful for spotting a spike after cooking or cleaning, not for judging safety — it lumps very different compounds into one number. A CO₂ sensor is a nice-to-have for ventilation.
In Indian cities with high pollution, plan to replace HEPA filters once a year. In less polluted areas or with lighter use, filters may last longer. Check the filter indicator if your purifier has one, or inspect the filter. If it looks grey or black, it's time to change.
Not entirely. A 2025 Kanpur study found that even with windows closed and the AC running in fresh-air mode, average in-cabin PM2.5 reached approximately 125 µg/m³. Switching to recirculation mode produced lower particle levels. However, prolonged recirculation can cause CO₂ to build up. One should switch briefly to fresh-air mode for about 5 minutes every 15–20 minutes to flush it out (Verma et al., Atmospheric Pollution Research, 2025).
Yes. A 2025 Mumbai study tracking 194 trips across seven commute modes found that in-cabin PM2.5 exposure was 60 to 80% higher during congested traffic conditions compared to free-flowing traffic. The longer you sit in a jam, the higher your exposure. This applies even in a closed, air-conditioned car (Patra and Phuleria, Atmospheric Pollution Research, 2025).
More often than your service manual recommends. A 2020 SAE technical paper reported that cabin-filter specifications used in many Indian vehicles were originally developed for lower-dust European conditions. Under India's higher dust and pollution loads, filters clog faster and may underperform before the standard replacement interval. In high-pollution cities like Delhi, Kanpur, or Mumbai, consider replacing every six months (Nimsatkar et al., SAE Technical Paper 2020-28-0016).
It can be, especially in hot weather. New car interiors off-gas volatile organic compounds (including formaldehyde) from dashboards, seat foam, adhesives, and carpets. A 2024 study found that on hot summer days, formaldehyde concentrations inside new vehicles can increase substantially and may exceed health-based guidelines. Interior surface temperature (not air temperature) is the key driver. In Indian summers, similar or higher concentrations are plausible. Park in the shade where possible and ventilate the car before getting in (Zhang et al., PNAS Nexus, 2024).
Yes, under the right conditions. A 2023 peer-reviewed study found that prolonged exposure to high humidity can allow potentially harmful moulds, including Aspergillus species, to grow on non-woven cabin filters and become airborne inside the cabin. India's monsoon season creates sustained high-humidity conditions that increase this risk. If your cabin filter has not been replaced after or during the monsoon, it is worth checking or replacing (Gołofit-Szymczak et al., Environmental Science and Pollution Research, 2023).
1T for rooms up to 120 sq ft, 1.5T for 120–200 sq ft, 2T for 200–320 sq ft, but these are starting points only. The actual requirement also depends on occupancy, direct sunlight, and whether the room is kitchen-adjacent. A slightly undersized AC struggles on hot days. A significantly oversized AC cools quickly but doesn't run long enough to remove humidity, leaving the room feeling cold and damp. Our [AC Finder](/tools/ac-finder) calculates adjusted tonnage based on all these factors.
BEE star ratings measure energy efficiency (specifically ISEER, the Indian Seasonal Energy Efficiency Ratio). A 5-star split AC typically has an ISEER of 4.5–5.8, while a 3-star split AC is around 3.8–4.4. At 8 hours/day and ₹8/kWh, a 5-star 1.5T AC might cost ₹6,000–₹7,000/year versus ₹8,000–₹9,500/year for a 3-star model. The gap becomes significant over 10 years, though 5-star units cost more upfront. Note: the BEE star scale is different for window ACs and split ACs. They cannot be directly compared by star rating alone.
No, not directly. Standard split and window ACs recirculate indoor air. They cool the room and reduce humidity but do not bring in fresh air, remove PM2.5, or lower CO₂ or VOCs. Running an AC for long periods in a closed room can cause CO₂ to build up. For PM2.5 removal, use a standalone HEPA air purifier. For CO₂ control, periodic ventilation is necessary.
Auto-dry runs the fan for a few minutes after the AC is switched off to dry the cooling coil and drip tray. Without this feature, standing water remains inside the unit and creates ideal conditions for mould and bacteria, especially during monsoon months. Once mould grows inside the unit, it gets blown into the room every time the AC runs. Auto-dry is one of the most important and underrated features when choosing an AC in India.
AmbientMax is the highest outdoor temperature at which the AC can still operate effectively. Most Indian split ACs are rated for 43–52°C; some premium models go up to 55–60°C. When outdoor temperature exceeds this rating, the outdoor unit struggles to reject heat, the compressor works harder, and the AC may underperform or trip. This is critical in cities like Nagpur, Jaipur, and Delhi where peaks often exceed 46–48°C. Our [AC Finder](/tools/ac-finder) compares each model's ambientMax against IMD peak temperatures for your city.
For most Indian users, yes. Copper coils are easier and cheaper to repair, more corrosion-resistant, and have lower biofilm adhesion than aluminium. Aluminium coils are used in some budget models but repairs usually require replacing the entire coil. The difference is especially important in coastal cities where corrosion risk is high.
A tropicalised PCB (printed circuit board) has conformal coating that protects it against high humidity and temperature. Standard PCBs can suffer oxidation and failure in humid conditions, leading to erratic behaviour or complete breakdown, common during monsoon and in coastal areas. Brands like Daikin, Panasonic, and O General use tropicalised PCBs in their India-specific models.
At least once a month during heavy use. In high-pollution cities (Delhi, Lucknow, Kanpur), clean every 2–4 weeks during peak summer and winter. Dirty filters reduce airflow, increase electricity consumption, and recirculate dust into the room. Most modern ACs have easy front-access filters that can be rinsed in under 5 minutes.
R32 is the standard refrigerant in most new Indian split ACs, replacing R410A. It has significantly lower global warming potential (GWP 675 vs 2088 for R410A), requires a smaller charge, and is cheaper to service. Under the Kigali Amendment, R410A is being phased down. R32 is the correct choice for any new AC in India.
Consider a hot and cold (reverse cycle / heat pump) AC only if you live in North India or hilly areas where winter temperatures regularly drop below 10°C. All current hot and cold models in India are 3-star rated. No 5-star versions exist yet. Minimum operating temperatures vary: Haier down to -15°C, Panasonic to -7°C, most others to -10°C. In Mumbai, Chennai, Bengaluru, Kochi, and most coastal and southern cities, a regular cooling-only AC is sufficient.
Independent real-world evidence for meaningful improvement in PM2.5, allergens, or bacteria in typical Indian homes is limited. Most manufacturer claims are based on lab tests with high pollutant concentrations that don't reflect normal home conditions. Some ionisers can generate ozone, which is a respiratory irritant. These features are not scored in our [AC Finder](/tools/ac-finder).
The cooling itself is safe. The concern is CO₂ buildup. In a closed bedroom with 2 people and an AC running all night, CO₂ levels rise steadily. Above 1000 ppm, cognitive function and sleep quality can decline. Above 1500–2000 ppm, stuffiness and poor sleep are common. A quick window opening before bed or a small ventilation gap prevents this. Use our [Ventilation Guide](/tools/ventilation-guide) to check when outdoor AQI and temperature make ventilation safe.
No. Indoor Air Guide is an independent, educational resource.