In 2020, Taiwan's Taichung began tracking haze for 3 years; by 2022, industrial solvents drove 57% of the chemistry behind organic haze, showing why cleaner air did not always mean clearer skies

Taiwan's air quality improved, yet hazy skies persisted over Taichung city. Researchers found organic particles, from industrial solvents, became the main haze contributor by 2022. This shift occurred as ammonium sulfate and nitrate levels decreased significantly. Reducing nitrogen oxides did not always clear the air due to atmospheric chemistry.