Aljazeera: Out of the world’s 100 most polluted cities, 94 are in India, China, and Pakistan…How is air quality measured? Air quality is determined by the levels of air pollutants PM2.5, PM10, ozone, nitrogen dioxide, sulfur dioxide, and carbon monoxide.Particulate matter (PM) comprises tiny particles that negatively impact health. PMs vary in size, most damaging… Continue Reading