Among the cities reporting to the World Health Organization, the following have the highest levels of particulate matter contributing to poor air quality: Chiang Rai, Ayutthaya, Saraburi, Phrae and Lampang.
Outdoor air pollution is a mix of chemicals, particulate matter, and biological materials that react with each other to form tiny hazardous particles. It contributes to breathing problems, chronic diseases, increased hospitalization, and premature mortality.
The concentration of particulate matter (PM) is a key air quality indicator since it is the most common air pollutant that affects short term and long term health. Two sizes of particulate matter are used to analyze air quality; fine particles with a diameter of less than 2.5 µm or PM2.5 and coarse particles with a diameter of less than 10 µm or PM10. PM2.5 particles are more concerning because their small size allows them to travel deeper into the cardiopulmonary system.
The World Health Organization’s air quality guidelines recommend that the annual mean concentrations of PM2.5 should not exceed 10 µm/m3 and 20 µm/m3 for PM10.
Cities and rural areas worldwide are affected by air pollution. When planning a trip, consider health status, age, destination, length of trip and season to mitigate the effects of air pollution.
Short term symptoms resulting from exposure to air pollution include itchy eyes, nose and throat, wheezing, coughing, shortness of breath, chest pain, headaches, nausea, and upper respiratory infections (bronchitis and pneumonia). It also exacerbates asthma and emphysema. Long term effects include lung cancer, cardiovascular disease, chronic respiratory illness, and developing allergies. Air pollution is also associated with heart attacks and strokes.
See city and country air pollution levels
World Health Organization
Health risk description last reviewed: June 16, 2016
Country information last updated: February 18, 2016