Atmospheric Heavy Metal Emissions and Health Risk Assessment

Atmospheric heavy metal emissions arise from both natural processes and anthropogenic activities, including fossil fuel combustion, industrial smelting, vehicular traffic and informal recycling. Once emitted, metals such as lead, cadmium, mercury and arsenic persist in the fine particulate fraction (PM2.5) or adhere to coarser dust, undergo long-range transport and accumulate in terrestrial and aquatic systems. Chronic and acute exposure to these metals via inhalation, ingestion or dermal contact can impair respiratory function, disrupt neurological development and increase carcinogenic risk. Health risk assessment combines emission inventories, atmospheric dispersion modelling, chemical speciation and receptor-modelling techniques to quantify source contributions and to estimate population-weighted exposure doses. Recent advances have improved temporal resolution of trace-metal monitoring, refined source apportionment through receptor models and incorporated bioaccessibility and dose–response relationships into risk metrics. The global significance of this work is reflected in policy developments on emission controls, industrial best practices and urban air-quality management, all aimed at reducing human health burdens and environmental disparities.

Research from Nature Portfolio

A seasonal study conducted in a city with prolonged winter heating revealed that coal combustion under heat-supply conditions drives spikes in PM1.0 and PM2.5 concentrations, with associated heavy metals and secondary pollutants peaking during cold months. Source apportionment identified major contributors as coal combustion, dust storms, straw burning and vehicular emissions. Zinc dominated the average daily dose via ingestion and inhalation, followed by lead, chromium, copper and manganese, while nickel, cadmium and cobalt contributed marginally. The work demonstrated that water-spray strategies, mimicking precipitation scavenging, could mitigate traffic- and coal-combustion related metal burdens in the urban atmosphere by promoting wet deposition.

Atmospheric Heavy Metal Emissions and Health Risk Assessment publication trend

The graph below shows the total number of articles in atmospheric heavy metal emissions and health risk assessment across all publications each year (not limited to Nature Index journals).

Technical terms

Particulate Matter (PM2.5): Fine airborne particles smaller than 2.5 µm in diameter that can penetrate deep into the lungs.

Source Apportionment: A set of statistical and receptor modelling methods used to identify and quantify emission sources contributing to ambient pollutant concentrations.

Enrichment Factor (EF): A ratio used to distinguish anthropogenic metal inputs from natural background levels by normalising to a reference crustal element.

Average Daily Dose (ADD): The amount of a contaminant ingested or inhaled per unit body weight per day, used in health risk assessment calculations.

References

1. Quantitative assessment of atmospheric emissions of toxic heavy metals from anthropogenic sources in China: historical trend, spatial distribution, uncertainties, and control policies. Atmospheric Chemistry and Physics (2015).
2. Ambient Air Heavy Metals in PM2.5 and Potential Human Health Risk Assessment in an Informal Electronic-Waste Recycling Site of China. Aerosol and Air Quality Research (2016).
3. Seasonal concentration distribution of PM1.0 and PM2.5 and a risk assessment of bound trace metals in Harbin, China: Effect of the species distribution of heavy metals and heat supply. Scientific Reports (2020).