Artificial rain efforts in Indonesia may exacerbate urban pollution, experts warn

INDONESIA: Researchers have shed light on a concerning aspect of weather modification technology (TMC) aimed at mitigating urban air pollution: the potential for worsening air quality through the use of artificial rain.

Indonesian governments had previously adopted weather modification technology (TMC) applications to curtail rain in efforts to alleviate air pollution levels, particularly within the Jakarta, Bogor, Depok, Tangerang, and Bekasi (Jabodetabek) region.

The Indonesia Meteorological, Climatological, and Geophysical Agency (BMKG) reported that TMC activities had been conducted in the western region of West Java across two distinct timeframes.

During the period from 19 to 21 August, TMC interventions led to reduced rainfall on 20 August.

This resulted in moderate to heavy precipitation in sections of Bogor Regency, as well as light to moderate rainfall in Depok (West Java), Lebak Regency, Tangerang Regency, and South Tangerang (Banten).

Subsequently, TMC activities from 27 August exhibited success in generating moderate to heavy rainfall across Bogor and Depok Regencies, while producing light to moderate precipitation in various parts of Bogor, Depok, Central Jakarta, West Jakarta, South Jakarta, East Jakarta, North Jakarta, and South Tangerang.

According to BMKG data, 13 flight sorties were conducted up to 27 August, distributing 8,800 kg of NaCl (Natrium Chloride) and 1,600 kg of CaO (Calcium Oxide).

Deni Septiadi, a meteorology researcher at BMKG, cautioned that the practice of dispersing salt into the atmosphere to induce rain could amplify the concentration of pollutants.

During a YouTube podcast on Wednesday (30 Aug), he elaborated, “Directly introducing salt into the Jakarta atmosphere and its environs could potentially lead to an increase in the concentration of pre-existing pollutants.”

Septiadi attributed this phenomenon to the prevailing dry conditions during the robust June, July, and August phases of the Australian Monsoon flow.

Moreover, the El Niño phenomenon has resulted in minimal water vapour within Indonesia’s maritime zones, notably impacting Jakarta and its vicinity.

He reiterated, “In the June to August period when conditions are arid and moisture is scarce, sprinkling salt should not be endorsed as a solution to urban pollution.”

Septiadi underscored that fine-diameter pollutants such as PM2.5 and PM10 should function as atmospheric aerosols akin to the salt (NaCl) used in TMC.

These pollutants ideally bind with water vapour to facilitate condensation, cloud formation, and subsequent rain.

However, the dilemma arises due to the absence of water vapour during dry spells, leading to the dispersal of pollutants in the atmosphere.

In conclusion, Septiadi emphasized that during the June to August period characterized by dry conditions and minimal moisture, the practice of salt dispersal should not be advocated as a viable pollution solution for urban areas.