Publications·December 30, 2022
Vietnam has achieved great progress in both economic growth and poverty reduction; nevertheless, this economic growth is accompanied by an increase in resource use and other negative externalities, such as air pollution. This contributes significantly to environmental degradation and public health issues, particularly regarding air quality in some major cities in the country, including Hanoi, the capital of Vietnam. The current air quality situation in Hanoi and its neighboring provinces of Bac Ninh and Hung Yen necessitates urgent action to reduce pollution levels, and, consequently, population exposure to harmful PM2.5 concentrations. Newly announced air quality-related policies, which will be in effect between 2021 and 2030, are an important step towards decreasing air pollution but do not appear to be sufficient to protect health in the medium-term, that is, until 2030. To explore management options available to policy makers in the near term, this study has developed new data and alternative scenarios analyzing the impact of various air quality measures and policies. Opportunities to achieve national standards across Hanoi and its surrounding areas were identified and provide input into policy discussions on an Air Quality Management (AQM) Plan for Hanoi and its surrounding provinces, as well as for Vietnam in general.
1 Context & motivation
Hanoi’s annual mean PM₂.₅ has never fallen below 35 µg m⁻³ since 2015, more than 1.4 × Vietnam’s national standard (25 µg m⁻³) and 7 × the 2021 WHO guideline (5 µg m⁻³).
Roughly 100 % of the 23 million inhabitants of the Hanoi-Red River Delta region already breathe air above the national limit; 40 % face >45 µg m⁻³.
Growth in coal-fired power, industrial clustering, exploding road traffic, open burning and ammonia from intensive farming threaten to push 2030 PM₂.₅ toward 60 µg m⁻³ under business-as-usual (BAU).
2 Method & scenarios
The team calibrated the GAINS-Vietnam integrated assessment model with:
A new bottom-up emission inventory (energy, industry, transport, agriculture, waste) for 2015.
One-year source-apportionment field campaign (PM₂.₅ monitoring + PMF) and fine-scale AERMOD runs for primary particles.
Regional meteorology and VIIRS fire counts to capture trans-boundary inflow.
Five 2030 scenarios were explored:
Scenario Core assumptions
Policies before 2020 (BAU) Existing laws, PDP-7 coal build-out, lax enforcement.
New policies from 2021 Draft PDP-8 (less coal, better plant efficiency), Hanoi waste-burn ban, tighter industrial limits.
New policies + NDC 2020 Adds 2020 NDC climate actions: renewables, EV uptake, energy efficiency, reduced fertiliser NH₃.
Maximum Technically Feasible Reduction (MTFR) All best-available filters & process changes regardless of cost; Asia-wide clean-air push cuts import plume.
Cost-optimal path to meet NAAQS GAINS optimisation picks the cheapest mix to reach 25 µg m⁻³ population-weighted PM₂.₅ across the three provinces.
3 Current source mix (2015 baseline)
Population-weighted contributions to Hanoi PM₂.₅:
Industry & power ≈ 35 % (steel, cement, coal CHP)
Transport (exhaust + road dust) ≈ 25 %
Ammonia from livestock & urea fertiliser ≈ 20 % (secondary ammonium sulphate/nitrate)
Residential biomass & coal cooking/heating ≈ 10 %
Open burning of crop residues & waste ≈ 7 %
Natural / long-range transport ≈ 3 %
Only one-third of PM₂.₅ originates inside Hanoi municipality; the remainder drifts in from neighbouring provinces, the wider North and even southern China.
4 2030 outlook & policy effectiveness
Metric BAU (policies < 2020) New policies 2021 + NDC 2020 Cost-optimal (NAAQS)
Hanoi mean PM₂.₅ (µg m⁻³) 60 48–50 30–35 ≤ 25
Population >45 µg m⁻³ ~70 % ~40 % 0 % 0 %
Marginal abatement cost – +US$0.6 bn yr⁻¹ +US$1.1 bn yr⁻¹ +US$1.4 bn yr⁻¹ (but health benefits ≈ US$2.5 bn yr⁻¹)
Key insights:
Newly announced measures alone cannot meet national standards; power-sector coal and traffic growth erase gains.
Climate-aligned actions (NDC 2020) halve PM₂.₅ yet still leave 85 % of people above 25 µg m⁻³.
The least-cost NAAQS portfolio is only ~30 % dearer than NDC measures but spares ~3 700 premature deaths yr⁻¹.
5 Sectoral levers to hit 25 µg m⁻³ by 2030
Sector Priority interventions (cost-effective set)
Power & industry No new sub-critical coal; retrofit existing units with high-efficiency ESP + FGD + SCR; tighten stack standards; accelerate rooftop & utility solar, wind, gas shift.
Craft villages & bricks Ban coal-fired batch kilns; transition to electric/LPG boilers; enforce 200 mg m⁻³ dust limit.
Transport 50 ppm → 10 ppm diesel sulphur; Euro VI/VI-c norms for new vehicles; low-emission zones; accelerate e-motorcycle, e-bus, EV taxi roll-out; pave & wet-clean urban roads.
Agriculture Ban open straw burning; replace urea with ammonium-nitrate; covered manure storage & biogas digesters.
Waste Enforce total ban on open municipal burning; divert organics to compost/anaerobic digestion; capture landfill methane.
These measures jointly cut local primary PM₂.₅ by 60 % and precursor SO₂/NOₓ/NH₃ by 40–55 %; imported pollution is reduced by coordinated regional standards and upstream coal controls.
6 Governance & finance roadmap
Regional airshed authority linking Hanoi, Bắc Ninh, Hưng Yên, other Red River provinces and MONRE for coherent standards, inventories and enforcement.
Legal upgrades: align NAAQS with WHO interim-2 (35 µg m⁻³ by 2025; 25 µg m⁻³ by 2030); publish sulphur-fuel road-map.
Monitoring & MRV: expand reference BAM/NO₂/SO₂/O₃ to hot-spot districts; integrate GAINS and low-cost sensor feeds; public data portal.
Finance: blend Pollution Management & Environmental Health (PMEH) trust-fund grants, green bonds, and climate finance (LEAP, ADB, JETP) to meet the US$1.4 bn yr-¹ investment need.
Enforcement: performance budgets for DONREs; vehicle I/M overhaul; zero-tolerance for high-smoke motorcycles and waste-burning.
7 Keywords
Hanoi PM₂.₅; GAINS model; cost-optimal portfolio; coal-power retrofit; craft-village emissions; low-sulphur diesel; EV transition; straw-burn ban; airshed governance; MRV system.