CO: 1054.03 (0–12400 µg/m³) – Carbon Monoxide – a colorless gas that limits oxygen delivery in the body. – Produced by incomplete combustion from vehicles, stoves and wildfires. High exposure reduces oxygen transport and can be life-threatening. (Low)
NO: 0.4 (0–200 µg/m³) – Nitric Oxide – reactive gas that contributes to ozone and smog formation. – Short-lived gas from fuel burning. Although unstable, it contributes to ground-level ozone and secondary pollutants. (Low)
NO2: 11.29 (0–200 µg/m³) – Nitrogen Dioxide – toxic reddish gas, linked to asthma and lung irritation. – Strongly traffic-related pollutant. Long-term exposure is associated with asthma, reduced lung function, and cardiovascular risk. (Low)
O3: 2.81 (0–180 µg/m³) – Ozone – harmful near the ground, formed when sunlight reacts with traffic and industrial emissions. – Unlike protective ozone in the upper atmosphere, ground-level ozone is harmful. It causes chest pain, coughing and worsens bronchitis. (Low)
SO2: 3.34 (0–250 µg/m³) – Sulfur Dioxide – pungent gas from coal and oil combustion, triggers respiratory issues. – Major contributor to acid rain. Short-term exposure irritates eyes, nose, throat and can trigger asthma attacks. (Low)
PM2_5: 76.06 (0–55 µg/m³) – Fine Particles (PM2.5) – microscopic dust and smoke that enter deep into the lungs. – Particles smaller than 2.5µm – from smoke, coal burning and vehicle exhaust. They bypass body filters and reach the bloodstream. (Very High)
PM10: 84.88 (0–250 µg/m³) – Coarse Particles (PM10) – larger dust, pollen and ash particles affecting breathing. – Particles up to 10µm – from construction dust, pollen and ash. Aggravates respiratory conditions like COPD and asthma. (Moderate)
NH3: 6.2 (0–1000 µg/m³) – Ammonia – gas mainly from agriculture and fertilizer use. – Emitted by livestock farming, fertilizers and some industry. Can form fine secondary particles when combined with NOx and SO2. (Low)
About Air Quality in Kathmandu
Kathmandu faces pollution from brick kilns, traffic, and seasonal weather inversions that trap smog.
