Urban atmospheric formaldehyde concentrations measured by a differential optical absorption spectroscopy method

Area of Science:

• Atmospheric Chemistry
• Air Quality Monitoring
• Environmental Science

Background:

• Formaldehyde (HCHO) is a significant air pollutant with complex sources and atmospheric behavior.
• Understanding HCHO concentrations is crucial for assessing urban air quality and public health.
• Shanghai, a major metropolitan area, faces challenges in managing air pollution.

Purpose of the Study:

• To monitor formaldehyde (HCHO) concentrations in Shanghai's ambient air over a one-year period.
• To investigate the diurnal and seasonal variations of HCHO.
• To explore the relationship between HCHO and ozone (O3) and identify influencing factors.

Main Methods:

• Differential Optical Absorption Spectroscopy (DOAS) was employed for HCHO monitoring.
• Measurements were conducted at a research station in Fudan University, Shanghai.
• Data collection spanned from April 2010 to April 2011, yielding over 120,000 data points.

Main Results:

• Average HCHO concentrations peaked in August 2010 (10.0 ppbv) and were lowest in April 2010 (2.0 ppbv).
• Diurnal variations of HCHO and O3 showed similar trends across all seasons, with strong positive correlation.
• Winter 2011 HCHO levels (~12.0 ppbv) were significantly higher than Spring 2010 (~2.0 ppbv), correlating with pollution control periods.

Conclusions:

• Seasonal variations in HCHO are influenced by anthropogenic activities, traffic, and atmospheric conditions.
• The observed HCHO trends suggest effectiveness of pollution control measures implemented around the EXPO 2010 period.
• This study provides essential data for understanding HCHO levels and chemical processes in large urban environments.