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 (fine particles from cooking, dust, smoke, and outdoor pollution seeping in), VOCs (volatile organic compounds from paints, cleaning products, new furniture, and air fresheners), CO₂ (from breathing, which indicates poor ventilation), NO₂ (from gas stoves and heaters), and biological pollutants (mold spores, pet dander, dust mites, pollen). In Indian homes, cooking emissions and outdoor pollution infiltration are often the biggest contributors to poor indoor air quality.
Common VOC sources to minimise or avoid include: synthetic air fresheners and room sprays, oil-based paints and varnishes (choose low-VOC or water-based alternatives), strong cleaning products with bleach or ammonia, new furniture and mattresses (let them off-gas outdoors or in ventilated areas first), nail polish and removers, mosquito coils and liquid vaporizers, and scented candles. When buying new items, look for 'low-VOC' or 'zero-VOC' labels. Good ventilation helps reduce VOC buildup from unavoidable sources.
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.
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). Add activated carbon if odours or chemical smells are a concern.
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, as it measures fine particle pollution, which is the main concern in Indian cities. A TVOC sensor is also important if you want to track gases from cooking, cleaning products, or new furniture. A CO₂ sensor is a nice-to-have for monitoring ventilation, but remember: air purifiers don't remove CO₂.
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.