Hermosillo faces a convergence of extreme heat, air pollution, and elevated pollen levels that can aggravate allergies and respiratory conditions, according to Carmen Isela Ortega Rosas, a researcher at the Universidad Estatal de Sonora (UES). As one of the warmest cities globally, the Sonoran capital experiences urban heat islands associated with periods of three or more consecutive days exceeding 44 degrees Celsius, compounding public health vulnerabilities tied to climate change.
Extreme Heat and Urban Air Quality in Hermosillo
Sustained high temperatures and minimal rainfall modify local vegetation cycles and can leave atmospheric particulate matter suspended across Hermosillo’s peripheral zones. According to data highlighted by the World Health Organization (WHO), outdoor air pollution is related to acute and chronic respiratory illnesses, cardiovascular complications, and other health effects. Climate variability studies place Hermosillo among the top ten warmest cities worldwide, noting that summer temperatures in specific urban sectors can reach up to 54 degrees Celsius due to sparse vegetation, pavement, and urban activity.
Shifting Pollen Seasons Driven by Climate Change
Rising temperatures and elevated carbon dioxide concentrations can advance the start of pollen seasons, prolong them, and increase the production of these allergens. Research coordinated through the Instituto de Ciencias de la Atmósfera y Cambio Climático (ICAyCC) at the Universidad Nacional Autónoma de México (UNAM) shows that native species that previously bloomed mainly during March and April can now begin that process as early as late January. This shift prolongs public exposure to bioaerosols, including plant pollen and fungal spores, which can trigger health issues ranging from rhinitis to asthma episodes in susceptible populations.
Decade-Long Aerobiological Monitoring in Sonora
To track these environmental triggers, researchers have participated for a decade in the Red Mexicana de Aerobiología, a project of UNAM’s ICAyCC. The specialized station operating in Sonora measures concentrations of airborne pollen and fungal spores. This ongoing data collection identifies periods of greater presence of these agents, offering reference points for people with allergies.
Urban Reforestation with Native Plant Species
To mitigate urban heat islands and improve local air quality, researchers advocate for nature-based solutions focused on increasing the presence of native trees in parks and urban spaces. Recommended climate-adapted species include:
- Palo fierro (Olneya tesota)
- Guamúchil (Pithecellobium dulce)
- Palo verde azul (Parkinsonia florida)
- Palo brea (Parkinsonia praecox)
- Mezquite terciopelo (Neltuma velutina)
Data indicates that while approximately 29 percent of plants present in Sonora are non-allergenic natives, urban parks and gardens are dominated by introduced species. Expanding the use of native species adapted to the environmental conditions of Sonora helps generate shade, favor local climatic conditions, and capture carbon dioxide.
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