Billions of people still breathe unhealthy air: new WHO data Over 6000 cities now monitor air quality 4 April 2022 News release Geneva, Switzerland record number of over 6000 cities in 117 countries are now monitoring air quality, but the people living in them are still breathing unhealthy levels of fine particulate matter and nitrogen dioxide, with people in low and middle-income countries suffering the highest exposures. A number of governments are taking steps to improve air quality, but the World Health Organization is calling for a rapid intensification of actions to: support the transition to the exclusive use of clean household energy for cooking, heating and lighting; build safe and affordable public transport systems and pedestrian- and cycle-friendly networks; and reduce agricultural waste incineration, forest fires and certain agro-

QUESTIONS
a) Identify ONE secondary air pollutant associated with the transport
sector and describe ONE practice that could be used to reduce or eliminate
its production. 

b) Describe ONE practice that could be used on farms to reduce the
production of particulates caused by the incineration of agricultural waste.

c) Explain whether thermal inversion would increase or decrease the
effects of air pollution. Please provide a description of thermal inversion in
your response.